Greetings RezaSoleimani ...
welcome to the forum ...
we can’t say for certain from the information that you’ve posted, but what has PROBABLY happened is that the RS-232 port on your SLC has been reconfigured for something OTHER THAN its default “programming” mode of operation ... this is frequently done to make the port compatible with HMIs and other peripheral devices ...
try this ... there is no guarantee that it will work, but it’s a good “first step” ... temporarily delete the DF1 driver and try using the PIC driver in RSLinx instead ... note that you will not be using an actual PIC converter (hardware) even though you will be using the PIC driver (software) ... the idea is that the DF1 driver that you’re (probably) using uses the DF1 protocol (language) ... the PIC driver uses the DH-485 protocol (language) ... if your port is indeed set up for DH-485 then the PIC driver should get you communicating ... if not, post again and we’ll try some more ideas ...
also ... in the future you should post your questions on the Q&A board ... this area that we’re in is for “practice” posts and not many people read these ...
you might have problems running the PIC driver ... some computer operating systems don’t like it ... post again if you need help and tell us what error messages you’re getting ... we can offer suggestions ...
another good thing to do ... if you already have an offline copy of the SLC’s program, open it up and look (Under Channel Config) at the configuration for Channel 0 ... that will give us a better idea of what we’re up against ...
good luck with your project ...